Reversible drive

ABSTRACT

A reversible drive of the belt-and-pulley type, comprising coaxial, axially spaced drive pulleys and coaxial, axially spaced idler pulleys offset to one side of the drive pulleys and rotatable about an axis perpendicular to and spaced laterally from the axis of the drive pulleys. An endless belt is trained around one of the drive pulleys, one of the idler pulleys, the other of the drive pulleys and the other of the idler pulleys, in that order. A movable mount for the idler pulleys slackens and tightens the belt, while a clutch respectively connects and disconnects the drive pulleys. With the belt slackened and the drive pulleys connected, a direct drive between the drive pulleys is obtained. With the belt tightened and the drive pulleys disconnected, a reverse drive between the drive pulleys is achieved. The belt is an O-ring the built-in memory of which causes it to tend to assume a circular configuration, whereby the belt inherently and automatically disengages the drive pulleys when the belt is slackened and the drive pulleys are connected in direct drive. This precludes rubbing of the belt in direct drive.

United States Patent Inventor Cornelius Wildhagen 5112 1/2 Tujunga Ave.,North Hollywood, Calif. 91601 Appl. No. 820,746 Filed May 1, 1969Patented Apr. 27, 1971 REVERSIBLE DRIVE 7 Claims, 8 Drawing Figs.

U.S. Cl 74/220, 74/227, 74/242. 15 Int. Cl Fl6h 7/02, Fl6h 7/ 1 2 Fieldof Search 74/220, 227, 242.15, 242.1 1

References Cited UNITED STATES PATENTS 815,433 3/1906 Johnson 74/220915,564 3/1909 Darling 74/220 1/1965 Hayes 74/220 PrimaryExaminer-Leonard H. Gerin Attorney-Harris, Kiech, Russell & KernABSTRACT: A reversible drive of the belt-and-pulley type,

comprising coaxial, axially spaced drive pulleys and coaxial,

axially spaced idler pulleys offset to one side of the drive pulleys androtatable about an axis perpendicular to and spaced laterally from theaxis of the drive pulleys. An endless belt is trained around one of thedrive pulleys, one of the idler pulleys, the other of the drive pulleysand the other of the idler pulleys, in that order. A movable mount forthe idler pulleys slackens and tightens the belt, while a clutchrespectively connects and disconnects the drive pulleys. With the beltslackened and the drive pulleys connected, a direct drive between thedrive pulleys is obtained. With the belt tightened and the drive pulleysdisconnected, a reverse drive between the drive pulleys is achieved. Thebelt is an O-ring the built-in memory of which causes it to tend toassume a circular configuration, whereby the belt inherently andautomatically disengages the drive pulleys when the belt is slackenedand the drive pulleys are connected in direct drive. This precludesrubbing of the belt in direct drive.

PATENTED APR 2 7 l97| SHEET 1 0F 2 INVENTOE' CORNELIUS 1 1/11. DHAGEN BH/S ATTORNEYS HARE/5} k/sc/g Pusssu d A-eu lRlEi/lElRSLlE naiveBACKGROUND OF INVENTION The present invention relates in general to areversible drive of the belt-and-pulley type and, more particularly, toa reversible drive comprising: a supporting structure; coaxial, axiallyspaced drive pulleys rotatably mounted on the supporting structure,either drive pulley being the driving or input pulley and the otherbeing the driven or output pulley; coaxial, axially spaced idler pulleysoffset to one side of the drive pulleys and rotatable about an axisperpendicular to and spaced laterally from the axis of the drivepulleys; an endless belt trained around one of the drive pulleys, one ofthe idler pulleys, the other drive pulley and the other idler pulley, inthat order; shiftable mounting means on the supporting structure andcarrying the idler pulleys for moving the idler pulleys .toward and awayfrom the drive pulleys to slacken and tighten the belt; clutch means forconnecting and disconnecting the drive pulleys; and actuating meansconnected to the mounting means and the clutch means, the actuatingmeans either engaging the clutch means to connect the drive pulleys andshifting the mounting means toward the drive pulleys to slacken thebelt, and thus achieving a direct drive between the drive pulleys, or,alternatively, disengaging the clutch means to disconnect the drivepulleys and shifting the mounting means away from the drive pulleys totighten the belt, and thus achieving a reverse drive between the drivepulleys.

SUMMARY AND OBJECTS OF INVENTION The primary object of the presentinvention is to provide a reversible drive of the foregoing type havingmeans for disengaging the belt from at least the drive pulleys when thebelt is slackened and the drive pulleys are connected in direct drive,thereby preventing rubbing of the belt.

Important objects of the invention are to provide a reversible drivewherein the belt-disengaging means is embodied in the belt itself and,more particularly, a reversible drive wherein the belt has a built-inmemory causing it, when unrestrained, to assume a configuration suchthat it holds itself away from at least the drive pulleys when the beltis slackened and the drive pulleys are connected in direct drive.

Still more particularly, an object of the invention is to provide aresilient belt of circular cross section having a built-in memorycausing it, when unrestrained, to assume a circular configuration.

An important object of the invention is to provide a reversible drive ofthe foregoing character wherein the belt is simply a conventional,commercially available, elastomeric O-ring. Such a device inherently hasthe built-in memory for a circular configuration which is necessary toenable it to operate as a self-disengaging belt in the mannerhereinbefore outlined.

Another object of the invention is to provide guard means for limitingoutward, self'disengaging displacement of the belt away from the drivepulleys and the idler pulleys when the belt is slackened and the drivepulleys are connected in direct drive.

Another important object is to provide a reversible drive wherein one ofthe drive pulleys is shiftable axially into and out of engagement withthe other to form the clutch means, and wherein the actuating means hasmeans for axially moving a corresponding portion of the belt toward thestationary drive pulley as the shiftable drive pulley is moved axiallytowards the stationary drive pulley. This keeps the belt properly inregister with the axially shiftable drive pulley.

Although usable for other purposes, a reversible drive utilizing aconventional O-ring as a clutch and a driving element in the reversemodels particularly suitable for use as a capstan drive in magnetic taperecording and/or playback equipment. In such an environment, thereversible drive is of a size readily lending itself to the use of aconventional O-ring as a self-disengaging belt in the direct mode. Theinherent ability of the O- ring belt to prevent rubbing in direct driveis especially important in tape equipment because it insures that thebelt will not act as a brake to tend to reduce the tape speed.

The foregoing objects, advantages, features and results of the presentinvention, together with various other objects, advantages, features andresults thereof which will be evident to those skilled in the reversibledrive art in the light of this disclosure, may be achieved with theexemplary embodiment of the invention described in detail hereinafterand illustrated in the accompanying drawings.

DESCRIPTION OF DRAWINGS In the drawings:

FIG. I is what may for convenience be described as a side elevationalview of a reversible drive of the invention, in its reverse mode;

FIG. 2 is an end elevational view, taken as indicated by the arrowedline 2-2 of FIG. 1;

FIG. 3 is a bottom plan view of the reversible drive in its reversemode;

FIG. 4 is a top plan view, partially in section, taken as indicated bythe arrowed line 4-4 of FIG. I, and showing the reversible drive in itsreverse mode;

FIG. 5 is an enlarged, vertical sectional view taken as indicated by thearrowed line 5-5 of FIG. 1 and showing the reversible drive in itsreverse mode;

FIG. 6 is a view similar to FIG. 1, but showing the reversible drive inits direct mode;

Similarly, FIG. 7 is a view similar to FIG. 5, but showing thereversible drive in its direct mode; and

FIG. 6 is a sectional view taken as indicated by the arrowed line ofFIG. 6, and showing the reversible drive in its direct mode.

DESCRIPTION OF EXEMPLARY EMBODIMENT OF INVENTION The reversible drive ofthe invention is designated generally in the drawings by the numeral 10and is provided with a suitable supporting structure or frame 12 shownas including a box section 14. In the construction illustrated, coaxiallower and upper drive shafts I6. and 18 respectively project upwardlyand downwardly into the box section 14 and are rotatably mounted insuitable thrust and journal bearings, not specifically identified,carried by the lower and upper portions of the box section.

The lower and upper drive shafts I6 and I8 respectively have connectedthereto coaxial, axially spaced, lower and upper drive pulleys 20 and22. The lower drive pulley 20 is vertically movable into and out ofengagement with the upper drive pulley 22, there being a pin 24 and slot26 connection.

between the lower drive shaft 16 and the lower drive pulley 20 to permitsuch vertical movement of the lower drive pulley. The upper drive pulley22 is rigidly connected to the upper drive shaft 18, as by a pin 28.

The upper end of the lower drive pulley 20 and the lower end of theupper drive pulley 22 constitute a clutch means 30 for connecting anddisconnecting the drive pulleys 20 and 22, the clutch means being showndisengaged in FIG. 5 and engaged in FIG. 7. Preferably, at least one ofthe drive pulleys, e.g., the drive pulley 22, is provided with a clutchfacing 32.

It will be understood that either of the drive shafts 16 and 18 may be adriving or input shaft, the other being a driven or output shaft. Theinput shaft may be driven in any suitable manner, and the output shaftmay drive any suitable device, such as a capstan of a magnetic taperecorder and/or playback apparatus.

Coaxial, axially spaced idler pulleys 356 are offset to one side of thedrive pulleys 20 and 22 and are rotatable about an axis perpendicular toand spaced laterally from the common axis of the drive pulleys. Theaxial spacing of the idler pulleys 36 is approximately equal to thediameter of the drive pulleys 20 and 22 and, conversely, the axialspacing of the annular grooves in the drive pulleys 20 and 22, when thelower drive pulley is in its lower position to disengage the clutchmeans 3%, is approximately equal to the diameter of the idler pulleys36.

An endless belt 40, to be described in more detail hereinafter, istrained around the lower drive pulley 20, one of the idler pulleys 36,the upper drive pulley 22 and the other idler pulley, in that order.Viewed differently, the endless belt 40 is trained around the lower andupper drive pulleys 20 and 22, and the resulting loops formed in theendless belt are then trained around the respective idler pulleys 36.With the dimensional relationships specified in the preceding paragraph, the angular wraps around the respective pulleys are allsubstantially l80, when the lower drive pulley 20 is in its lowerposition to disengage the clutch means 30. Thus, all the interpulleyruns of the endless belt 40 are substantially paral lel, under suchconditions.

The idler pulleys 36 are carried by a shiftable mounting means 42 formoving them toward and away from the drive pulleys 2t) and 22 to slackenand tighten the belt 40, the belt being shown slackened in FIGS. 6 to 8and being shown tightened in FIGS. I to 5. More particularly, theshiftable mounting means 42 comprises depending arms 4- 3 of a crank 46which is pivotally mounted on the frame 112 at 48. The idler pulleys 36are rotatably mounted on the respective depending arms 44 at 54 As willbe apparent, pivoting of the crank 46 in the clockwise direction, asviewed in FIGS. I and 6, results in slackening of the belt 41 The crank46 is biased in the counterclockwise direction, to tighten the belt 40,by a tension spring 52 connected at one end to the frame I2 and at itsother end to an arm 54 of the crank 46 which projects from the pivotpoint 48 toward and past the drive pulley axis. The crank 46 may bepivoted in the clockwise direction to slacken the belt 40 in anysuitable manner. In the construction shown, a solenoid 56 mounted on theframe 12 acts on an armature 58 pivoted on the frame at 64 and connectedto the crank arrn $4 by a cable 62. As will be apparent, when thesolenoid 56 is energized, it attracts the armature b, which pivots thecrank 46 in the clockwise direction in opposition to the action of thetension spring 52.

Referring to FIGS. 5 and 7, the lower drive pulley is provided in itslower end with a central recess 66 for a plunger 68 having an externalannular flange 70 below the lower drive pulley. Laterally spaced,coaxial, headed pins 72 extend inwardly through vertical slots 74 in thesides of the box section I41 of the frame 12, and are secured at theirinner ends to the plunger flange 70, as by being threaded thereinto. Theplunger 68 is biased downwardly against an annular seat 76 bycompression coil springs '73, FIGS. I and 6, seated at their upper endsagainst the frame I2 and seated at their lower ends on the heads ofscrews Sill slidable vertically relative to the frame I2 and threadedinto the plunger flange 70.

When the crank 46 is pivoted in the clockwise direction, as viewed inFIGS. I and 6, to slacken the belt 40, the plunger 68 is lifted, afterthe belt has been slackened, to cause the plunger to lift the lowerdrive pulley 20 into frictional engagement with the upper drive pulley22, thereby engaging the clutch means 30 to provide a direct driveconnection between the lower and upper drive pulleys. This effect isachieved by depending links 82 pivotally connected at their upper endsto the crank arm 54, and having at their lower ends vertical slots 84receiving therein the pins 72 connected to the plunger flange 70. Withthis construction, as the crank is pivoted in the clockwise direction toslacken the belt sit), it also, through the links 22, causes the plunger68 to lift the lower drive pulley 20 to engage the clutch means 30. Theslots 64 in the lower ends 1 of the links 32 serve to permit slackeningof the belt at) before engagement of the clutch means 30.

Considering the operation of the reversible drive I0 as thus fardescribed, it will be apparent that when the crank $6 is in the positionshown in FIGS. i to 5 of the drawings, the belt 40 is tightened by thetension spring 52 and the clutch means 30 is disengaged. Under suchconditions the reversible drive It) operates in its reverse mode, thelower and upper drive pulleys N and 22, and thus the lower and upperdrive shafts I6 and I8, rotating in opposite directions. However, whenthe solenoid 56 is energized to pivot the crank 46 in the clockwisedirection, or when the crank is thus pivoted in any suitable manner, theidler pulleys 36 are first moved toward the drive pulleys 20 and 22 toslacken the belt 40, and the lower drive pulley 20 is then movedupwardly into engagement with the upper drive pulley 22 to engage theclutch means 30 connecting the two drive pulleys together. Under suchconditions, the reversible drive 10 operates in its forward or directmode, the two drive pulleys being frictionally coupled together torotate in unison.

The endless belt 40 constitutes means for disengaging itself from thepulleys 20, 22 and 36, and particularly the drive pulleys 20 and 22,when the belt is slackened and the clutch means 30 engaged so that thereversible drive It) operates in the direct mode, thereby preventingrubbing contact between the drive pulleys and the belt, and consequentpossible speed reduction and/or damage to the belt.

The foregoing self-disengaging eifect is achieved by providing the belt40 with a circular configuration, now shown, when unrestrained, and byproviding it with a memory for that configuration. Consequently, whenthe belt 40 is slackened, it tends to resume its circular configuration,whereupon it displaces itself outwardly away from the various pulleys,and

especially the drive pulleys 20 and 22, as shown in FIGS. 6 to 8 of thedrawings.

Still more particularly, the foregoing effect can be achieved readily byutilizing for the endless belt 40 a conventional, commerciallyavailable, elastomeric O-ring of suitable dimensions. This provides avery simple and inexpensive self-disengaging belt 40, which is animportant feature of the invention.

Guard means are provided for limiting outward displacement of the beltaway from the drive pulleys 2i and 22 and the idler pulleys 36 when thebelt is slackened. More particularly, the crank arms 44 carrying theidler pulleys 36 are provided thereon with crescent-shaped guards 88within which the endless belt 48 fits relatively closely, as shown inFIG. I, when it is tightened. The sides of the box section 14 of theframe R2 are provided with lower and upper guard grooves W and 92 forreceiving therein corresponding portions of the belt 40 when slackened,and for limiting outward displacement of such Mlt portions away from thelower and upper drive pulleys 20 and 22. The upper guard grooves 92register with the annular groove in the upper drive pulley 22, and thelower guard grooves register with the upper position of the annulargroove in the lower drive pulley 2b, as shown in FIG. '7.

To insure outward expansion of the corresponding portion of the belt 40into the lower guard grooves 90 upon upward shifting of the lower drivepulley 20 to engage the clutch means 30, the crank arms 44 are providedthereon with inwardly extending, coaxial pins 94 which engage the beltloop around the lower drive pulley 20 and shift it upwardly intoregister with the lower guard grooves 90 as the lower drive pulley 20 isshifted upwardly in engaging the clutch means 30. This belt loop engagessuitable stops 96, FIG. 6, to limit upward displacement by the pins 94.

With the foregoing construction, when the crank 46 is pivoted in theclockwise direction, as viewed in FIGS. It and 6, to slacken the endlessbelt 40, the belt tends to disengage itself from all of the pulleys 20,22, and 36. Since the guards 88 are quite close to the idler pulleys 36,the outward displacement of the belt 40 adjacent the idler pulleys islimited. This causes the loops in the belt leading to the drive pulleys20 and 22 to move toward the drive pulleys to provide greater outwarddisplacement of the belt adjacent the two drive pulleys to insureagainst any rubbing contact in the direct mode, as clearly shown inFIGS. 7 and 8 of the drawings. As previously explained, the pins 94 onthe crank arms 44 insure maintaining the belt loop leading to the lowerdrive pulley 22 in register with the annular groove therein.

Although an exemplary embodiment of the invention has been disclosedherein for purposes of illustration, it will be understood that variouschanges, modifications and substitutions may be incorporated in suchembodiment.

lclaim:

1. In a reversible drive of the belt and pulley type, the com binationof:

a. a supporting structure;

b. coaxial, axially spaced drive pulleys rotatabiy mounted on saidsupporting structure;

c. coaxial, axially spaced idler pulleys offset to one side of saiddrive pulleys and rotatable about an axis perpendicular to and spacedlaterally from the axis of said drive pul leys;

. an endless belt trained around one of said drivepulleys, one of saididler pulleys, the other of said drive pulleys and the other of saididler pulleys, in that order;

. shittable mounting means on said supporting structure and carryingsaid idler pulleys and movable toward and away from said drive pulleysto slacken and tighten said belt;

engageable and disengageable clutch means for connect ing anddisconnecting said drive pulleys;

g. actuating means connected to said mounting means and said clutchmeans for either engaging said clutch means to connect said drivepulleys and shifting said mounting means toward said drive pulleys toslacken said belt, and thus achieve a direct drive between said drivepulleys, or, alternatively, disengaging said clutch means to disconnectsaid drive pulleys and shifting said mounting means away from said drivepulleys to tighten said belt, and thus achieve a reverse drive betweensaid drive pulleys; and

h. said belt having a circular cross section and having a built-inmemory causing it, when unrestrained, to assume a circular configurationso that said belt acts as a belt disengaging means for disengagingitself from at least said drive pulleys when said drive pulleys areconnected in direct drive and said belt is slackened.

2. A reversible drive according to claim 1 wherein said belt is anO-ring.

3. A reversible drive as set forth in claim 2 wherein said supportingstructure includes guard means limiting outward displacement of saidbelt away from said drive pulleys when said drive pulleys are connectedin direct drive and said belt is slackened.

4. A reversible drive as defined! in claim 3 wherein one of said drivepulleys is shiftable axially toward and away from the other by saidactuating means to engage and disengage said clutch means, and whereinsaid actuating means includes means for axially moving a correspondingportion of said belt toward the stationary drive pulley when axiallymoving said shiftable drive pulley toward said stationary drive pulley.

5. A reversible drive according to claim 3 wherein said mounting meansincludes guard means limiting outward displacement of said belt awayfrom said idler pulleys when said drive pulleys are connected in directdrive and said belt is slackened.

6. A reversible drive as defined in claim 1 wherein said actuating meanscomprises a crank having arms carrying said idler pulleys and an armconnected to said clutch means.

7. In a belt and pulley drive, the combination of:

a. pulleys rotatable about axes at angles to each other;

b. a belt trained around said pulleys in sequence;

c. means for moving at least one of said pulleys toward and away fromanother thereof to slacken and tighten said belt;

d. said belt having a circular cross section and having a built-inmemory causing it, when unrestrained, to assume a circularconfiguration; and

e. whereby said belt inherently disengages at least one of said pulleyswhen slackened.

1. In a reversible drive of the belt and pulley type, the combinationof: a. a supporting structure; b. coaxial, axially spaced drive pulleysrotatably mounted on said supporting structure; c. coaxial, axiallyspaced idler pulleys offset to one side of said drive pulleys androtatable about an axis perpendicular to and spaced laterally from theaxis of said drive pulleys; d. an endless belt trained around one ofsaid drive pulleys, one of said idler pulleys, the other of said drivepulleys and the other of said idler pulleys, in that order; e. shiftablemounting means on said supporting structure and carrying said idlerpulleys and movable toward and away from said drive pulleys to slackenand tighten said belt; f. engageable and disengageable clutch means forconnecting and disconnecting said drive pulleys; g. actuating meansconnected to said mounting means and said clutch means for eitherengaging said clutch means to connect said drive pulleys and shiftingsaid mounting means toward said drive pulleys to slacken said belt, andthus achieve a direct drive between said drive pulleys, or,alternatively, disengaging said clutch means to disconnect said drivepulleys and shifting said mounting means away from said drive pulleys totighten said belt, and thus achieve a reverse drive between said drivepulleys; and h. said belt having a circular cross section and having abuiltin memory causing it, when unrestrained, to assume a circularconfiguration so that said belt acts as a belt disengaging means fordisengaging itself from at least said drive pulleys when said drivepulleys are connected in direct drive and said belt is slackened.
 2. Areversible drive according to claim 1 wherein said belt is an O-ring. 3.A reversible drive as set forth in claim 2 wherein Said supportingstructure includes guard means limiting outward displacement of saidbelt away from said drive pulleys when said drive pulleys are connectedin direct drive and said belt is slackened.
 4. A reversible drive asdefined in claim 3 wherein one of said drive pulleys is shiftableaxially toward and away from the other by said actuating means to engageand disengage said clutch means, and wherein said actuating meansincludes means for axially moving a corresponding portion of said belttoward the stationary drive pulley when axially moving said shiftabledrive pulley toward said stationary drive pulley.
 5. A reversible driveaccording to claim 3 wherein said mounting means includes guard meanslimiting outward displacement of said belt away from said idler pulleyswhen said drive pulleys are connected in direct drive and said belt isslackened.
 6. A reversible drive as defined in claim 1 wherein saidactuating means comprises a crank having arms carrying said idlerpulleys and an arm connected to said clutch means.
 7. In a belt andpulley drive, the combination of: a. pulleys rotatable about axes atangles to each other; b. a belt trained around said pulleys in sequence;c. means for moving at least one of said pulleys toward and away fromanother thereof to slacken and tighten said belt; d. said belt having acircular cross section and having a built-in memory causing it, whenunrestrained, to assume a circular configuration; and e. whereby saidbelt inherently disengages at least one of said pulleys when slackened.